<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8">
    <title>Title</title>
    
    <style>
      .box {
        display: flex;
        column-gap: 10px;
      }
      
      .card {
        width: 200px;
        height: 50px;
        margin: 10px;
        padding: 10px;
        display: flex;
        justify-content: center;
        align-items: center;
        border: 1px black solid;
      }
    </style>
  </head>
  
  <body>
    <div id="app">
      <div class="box">
        <div class="card" v-if>v-if</div>
        <div class="card" v-if="true">true</div>
        <div class="card" v-if="false">false</div>
        <div class="card" v-if="booleanValue">booleanValue</div>
        <div class="card" v-if="'string'">string</div>
      </div>
    </div>
  </body>
  
  <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
  
  <script>
    Vue.createApp({
      data() {
        return {
          // 试着修改以下属性值，看看HTML中的变化
          booleanValue: true,
        };
      },
    }).mount('#app');
  </script>
</html>